As of linux 2.6.31 there is no mainline support for the Ralink rt2680 Wifi chipset.
While there is an official driver provided by Ralinktech, it is incompatible with 2.6.31 due to the fact that post 2.6.29 the kernel's net_device_opsAPI has changed and 2.6.31 also removed CONFIG_COMPAT_NET_DEV_OPS backwards compatibility.